Spring Injecting util:map in Kotlin with type safety - spring

Question

I have the several bean definitions in XML to store my SQL externally. I want to inject them in Kotlin as Map<String,String> however the only way I've been able to make it work so far it injecting it as Map<Any,Any>. Is there a way to ensure type safety here. Injecting it as Map<Any,Any> feels ghetto.
When I try Map<String,String> or even Map<String,Any> I get not qualifying beans found...
Example XML
<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<util:map id="brandSql" key-type="java.lang.String" value-type="java.lang.String">
<entry key="selectBrands">
<value type="java.lang.String">
<![CDATA[
SELECT
ID,
NAME
FROM BRAND
]]>
</value>
</entry>
</util:map>
</beans>
Injection into service
#Service
open class JdbcBrandService #Autowired constructor(
private val namedJdbcTemplate: NamedParameterJdbcTemplate
): BrandService {
companion object {
val logger = LoggerFactory.getLogger(JdbcBrandService::class.java)
}
#Autowired
#Qualifier(value = "brandSql")
private lateinit var queries: Map<Any,Any>
/// methods and what not go here
}
In Java I can get away with doing something like the following, but Kotlin's type system being more strict seems to prevent this.
#RestController
public class JavaBrandController {
private final Map<String, String> brandSql;
#Autowired
public JavaBrandController(#Qualifier("brandSql") Map sql) {
this.brandSql = sql;
}
#GetMapping("/javaBrands")
public Map getBrandSql() {
return this.brandSql;
}
}

Answer 1

Personally, it feels strange to have beans floating around that are of such generic types as Map<String, String>. It would create confusion when you need other maps.
What I would do is create a container class that holds a reference to the map, so you have a proper type to reference.
Example:
class SqlConfig(val map: Map<String, String>)
Then create a bean of this type in your xml:
<util:map id="brandSql" key-type="java.lang.String" value-type="java.lang.String">
<entry key="selectBrands">
<value type="java.lang.String">
<![CDATA[
SELECT
ID,
NAME
FROM BRAND
]]>
</value>
</entry>
</util:map>
<bean id = "sqlConfig" class = "test.package.SqlConfig">
<constructor-arg ref = "brandSql"/>
</bean>
Now you can autowire it as needed with the proper type in a non-guetto way:
#Autowired
#Qualifier(value = "sqlConfig") // <-- the qualifier is no longer needed
private lateinit var queries: SqlConfig